Learn to visualize and create shots in your head. A big thing for me is line. I love using lines to help frame up shots. For example, I took a self portrait of myself, look at how the lines coincide with one another. I am standing straight, that is a vertical line , my sweatshirt has vertical lines, the bars to my left are vertical. Also, my sunglasses create a horizontal line that match up with the bricks on the wall that create horizontal lines, there are more "organic and natural lines" I could name, but if you look hard enough you will see them.
And, get photoshop, even elements would work grade, that portrait of myself is color graded and touched up. Here is another shot I took of my wolfdog when she was a puppy, I like the framing and color grading I applied to it, not my best photo, but a favorite.